This invention relates to electronic power amplifiers.
There are many different types of power amplifiers available with different tradeoffs. Class AB amplifiers are good for high linearity and low cost structure but have high power dissipation. Most Class D amplifiers add the cost of output inductors and can produce difficulties with EMI but have low power dissipation. Sometimes the power supply voltage on a Class AB amplifier is modified with a Class D regulator in order to have some of the benefits of a Class AB amplifier and some of a Class D amplifier.
In power supply generation circuitry, single inductor multiple output (SIMO) regulators have been used to share one inductor for multiple outputs. These regulators, however, have not been successfully used as amplifiers in the past when used with other functions. Also, non-PWM (pulse width modulation) variations on Class D amplifiers such as PDM amplifiers are also collectively included in the Class D classification in this disclosure.
What is needed is an amplifier that has the advantages of a Class D amplifier with its high efficiency but with reduced expense and reduced EMI problems.